Well, the money part is always important to me. Fitting comfortably inside the GT40 would also be very important. Kit quality, including the least amount of deviation from the original design, is important. Customer service, if needed, is very important too. I bought my Kirkham partially due to the outstanding customer service that Kirkham gives their customers. The pedigree thing is way down the list. If all other things were equal, which they never are, then the SPF would probably be the choice because of the pedigree.
Due to time and technical skill limitations, I'm farily sure that I would like to get a turnkey minus car. About 5'11" and 175lbs, so I'm no Dean and I'm
definitely no Jamo, at least based on reputation.
BTW, the Kirkham has a new (temporary) address.